1. Field of the Invention
This invention relates to a camera system which comprises a camera body and accessories of varied kinds such as a lens, a flash device, etc. mounted on the camera body.
2. Description of the Related Art
Camera system of the kind arranged to store various data necessary for photographing at a ROM (a read-only memory or an information fixed storage circuit) disposed within such an accessory as an interchangeable lens or a flash device to be mounted on the camera body and to have the stored data supplied to the camera body in photographing by designating an applicable address of the ROM have been known. An example of such a camera system was disclosed in U.S. Pat. No. 4,529,288. When the amount of data to be handled in the camera system of this kind increases, however, the number of signal lines for addresses must be increased accordingly. Further, since the camera body must be arranged to perform control directly over each of the accessories on the basis of the data obtained by the address designation, the soft- and hardwares to be arranged on the side of the camera body inevitably becomes complex. To solve this problem, there has been proposed in Japanese Laid-Open Patent Application No. SHO 60-26324 a camera system which is arranged to have a microcomputer disposed also within the above-stated accessory and to have common data transmission lines arranged to permit communication between the microcomputer of the accessory and another microcomputer disposed within the camera body.
However, in the event of an error which arises on a transmission line in transmitting a command or instruction from the microcomputer of the camera body to each of the accessories due to a stain on an electric contact or the rust thereof or due to an external noise or the like thus resulting in an erroneous or unexecutable instruction, the microcomputer arranged within the camera body of the above-stated camera system is incapable of detecting the occurrence of the trouble and thus has been unable to take any apposite action. Further, the microcomputer within the camera body is incapable of detecting whether or not the instruction given to the accessory is actually carried out and thus has sometimes failed to adequately perform subsequent actions.